Deactivation mechanism of Cu/SiO₂ catalyst in gas phase hydrogenation of furfural to furfuryl alcohol

The Cu/SiO₂ catalysts were prepared by co-precipitation and tested for hydrogenation of furfural to furfuryl alcohol in a fixed bed reactor. The deactivation mechanism of the catalysts was investigated by characterization of H₂-TPR, ICP-OES, XPS, TG, Raman and TEM. Under the conditions of atmospheric pressure, reaction temperature of 140 ℃, mass space velocity of 2.4 h⁻¹ and the molar ratio of hydrogen to furfural of 9.7, the furfural conversion was higher than 97% in the first 5 h. However, the conversion of furfural decreased rapidly from 96% to 32% after 21 h of reaction, indicating that Cu/SiO₂ catalyst was rapidly deactivated. The factors for the deactivation of Cu/SiO₂ catalyst were the agglomeration and sintering of the active component copper. Moreover, the carbon deposition on the catalyst surface resulted in the covered active site Cu⁰.